The present invention generally relates to packages to be filled with a product on a form, fill, and seal machine and, more particularly, to a reclosable package filled through its top on a form, fill, and seal machine.
A typical reclosable package includes first and second opposing panels joined to each other along a pair of sides and a bottom bridging the pair of sides. A reclosable fastener extends along a package top disposed opposite the bottom. The fastener generally includes first and second opposing tracks. The first track includes a first profile, while the second track includes a second profile adapted to releasably interlock with the first profile. The first and second tracks are thermally fused to, or integrally formed with, the respective first and second panels. To open and close the fastener, the package may be provided with a slider mounted to the fastener.
If reclosable packages of the foregoing type are to be prepackaged with a product and then sold in a store, the packages are typically prepared on a horizontal or vertical form, fill, and seal machine. In the form, fill, and seal machine, the package is first formed into the shape of a pouch having a fill opening at either the top or the bottom. If the fill opening is disposed at the bottom, then the top is sealed prior to filling the package. Similarly, if the fill opening is disposed at the top, then the bottom is sealed prior to filling the package. Next, the package is filled with the product via the fill opening. Finally, the fill opening is sealed shut to fully enclose the product within the package. If the product delivered to the package includes food, then the fill opening is typically provided at the package bottom and a tamper-evident feature is provided along the top. The tamper-evident feature indicates to a consumer whether or not the package has been tampered with prior to purchase.
Some reclosable packages include a gusset along the bottom which expands in response to filling the package with a product. The gusset is advantageous because it increases the volume of product that can be contained in the package and, when the gusset expands, it allows the package to stand up on a store shelf. The stand-up package obviates the use of additional features such as headers with holes for hanging the package from a hook or post. The bottom gusset, however, makes it less practical to provide a fill opening at the bottom because most of the product resides in the gusset.
As a result, it is desirable to provide a fill-through-the-top reclosable package. One example of such a package is disclosed in U.S. Pat. No. 6,071,011 to Thomas et al. The Thomas patent discloses a fill-through-the-top reclosable package including first and second opposing body panels joined to each other along a pair of sides and a bottom bridging the pair of sides. A fastener, including first and second opposing tracks, extends along a package top disposed opposite the bottom. The first and second opposing tracks include respective first and second interlocking profiles and respective first and second fins extending from the respective first and second profiles. To provide tamper evidence, the first and second fins are joined to each other along a preferential line of weakness. While the first fin is attached to the first panel, the second fin is initially at least partially unattached to the second panel so as to provide a fill opening between the second fin and the second panel.
After the package is filled with a product via the fill opening, a sealer generates a seal between the second fin and the second panel to seal the fill opening. Unless precise operational control is maintained over such variables as the temperature, pressure, and dwell time of the sealer, the sealer could transfer excessive heat to the fins during the sealing process. Such excessive heat could deform the fins, cause the fins to stick to each other, or even accidentally seal the fins to each other. This, in turn, could make it difficult for the consumer to properly open the sealed package.
To overcome the potential shortcomings noted above, the present invention is directed to a fastener for a top-filled tamper-evident reclosable plastic package. The package includes first and second opposing panels joined along a pair of sides and a bottom bridging said sides. The fastener includes first and second opposing tracks along a top of the package. The first and second tracks include respective first and second interlocking profiles and respective first and second fins extending from the respective first and second profiles. The first and second fins are joined to each other at their respective lower ends. A preferential area of weakness is disposed along or near the juncture of the first and second fins. While the fastener is attached to the first panel, the fastener initially is at least partially unattached to the second panel so as to allow the package to be filled with a product via a fill opening between the fastener and the second panel. After filling the package with the product, the fill opening is sealed. In accordance with the present invention, the fastener includes special structure added proximate the fins to prevent the fins from being deformed, being stuck to each other, or being accidentally sealed to each other while sealing the fill opening.
In one embodiment, the special structure includes an additional fin extending from the second track and disposed generally alongside the second fin. The additional fin initially is at least partially unattached to the second panel while the first fin is attached to the first panel so as to allow the package to be filled with a product via a fill opening between the fastener and the second panel. After the package is filled with the product, the additional fin is attached to the second panel to seal the fill opening. This embodiment may be slightly modified to include another additional fin extending from the first track and disposed generally alongside the first fin. In this case, instead of attaching the first fin directly to the first panel, the another additional fin is attached to the first panel.
In another embodiment, the special structure includes a fin extension extending from the lower end of the second fin. The second fin and the fin extension initially are at least partially unattached to the second panel while the first fin is attached to the first panel so as to allow the package to be filled with a product via a fill opening between the fastener and the second panel. After the package is filled with the product, the fin extension is attached to the second panel to seal the fill opening. This embodiment may be slightly modified to include another fin extension extending from the lower end of the first fin.